It might not go
that bad. But I suspect that as medical imaging hardware becomes better, we'll eventually face a crisis point: we'll be forced to re-evaluate most of what we call "character traits" and reclassify them as neurochemistry quirks. This is an important distinction, because as a society, we tend to hold people responsible for their character, but not for bugs in their brain.
We can already see some of this today. Many people that would've been shunned by society in the past as "unstable" and "crazy", can be fixed by giving them lithium. We know not to fault a person for what's just a bug in their hardware. Similarly, many people that today are called "lazy" or "annoying", and blamed for their obviously flawed character, can be instantly fixed by low doses of stimulant medication. This is something most people didn't get a memo on yet.
I find it highly likely that most homicides are also driven by fixable neurochemistry quirks, and that we'll learn to identify and fix them at some point, and we'll be appalled at the ease with which we jumped to killing people for having them.